Electromagnetic interference (EMI) signals can adversely affect the performance and function of electrical devices. Some electrical devices can be sensitive to radiated EMI signals from other devices. For example, a low noise amplifier may provide substantial gain to an input signal; however, the performance of the amplifier may be negatively affected by the presence of interfering EMI signals on the amplifier inputs. The EMI signals can distort or otherwise cause errors in the sensitive input section and as a result the output of the amplifier can become distorted. To protect electrical devices from receiving unintentional EMI radiation, the strength of emitted electromagnetic interference is typically regulated by governmental agencies.
A common device used to control both emission and reception of EMI signals is a metallic shield employed to cover electrical components. The shield protects sensitive electrical parts from receiving stray EMI signals and can also limit the radiation of EMI signals. Shields function by providing a low impedance pathway for EMI signals. Shields are typically constructed of metal, such as steel or, in some instances, can be constructed with conductive paint over an insulator such as plastic.
As described, traditional shield implementations cover one or more electrical components. Unfortunately traditional shield implementations can increase area used on supporting substrates such as a printed circuit board (PCB). Increased area can be due, at least in part, to air gaps commonly used between protected components and the shield. The air gap may ease assembly and installation of the shield on the supporting substrate. As product designs are driven smaller, the areas of related modules such as printed circuit boards are driven to be smaller as well. Thus, there is a desire to decrease the area need to support shield implementations, particularly on supporting substrates such as PCBs.
Therefore, what is desired is space efficient shield assembly to attenuate interfering electrical signals for use on supporting substrates.